It is common practice to provide roof vents in buildings, for heat removal and other ventilating purposes, especially in buildings having large enclosed, high-roofed areas such as warehousing and manufacturing facilities. The roof ventilation systems known in the prior art include passive systems which depend primarily on the natural upward flow of warm air relative to cooler air, and systems which utilize power actuated fans or turbines to force air from the area immediately below the roof of the building through some form of passageway penetrating the roof.
Various approaches to vent an enclosed area through the roof have been attempted and are known in the prior art, but none of the approaches have successfully addressed providing a simple, quiet, and economically efficient apparatus and method of use to accomplish the task of quietly removing large volumes of air from an enclosed area through the roof thereof. Some approaches to power actuated ventilation systems which are known within the prior art typically use air passageway designs in which the air flow is not linear through the passageway, but is curved in some manner in an effort to prevent the entry of rain into the interior of the building through the passageway. Other approaches to power actuated ventilation systems utilize a linear passageway with a flapper valve or other closure means which depends upon the flow of air to hold the closure means in an open position during operation of a fan used to move the air through the system. In the approaches to those systems of the prior art, the air flow through the passageway is restricted, either by turbulence alone or in combination with the force of the closure means. As a result of the restriction and resulting turbulence, it has been necessary to employ fan motors of relatively high power, and correspondingly high noise levels and increasingly higher cost and power usage. Further, the air turbulence associated with such systems creates relatively high noise levels in addition to the fan motor noise. In addition, the ventilation systems of the prior art are typically uninsulated and do not attempt to inhibit heat loss through such systems. Also, the ventilation systems of the prior art typically do not effectively seal the air passageway against passive flow of air when it is not desired to remove air from the interior of the building and the fan is inactive.
U.S. Pat. No. 2,299,317 to Fink discloses a closure for roof hatches wherein a strictly manual means is employed to mechanically lift and swing open the hatch closure by using a rotatable worm gear and mating worm wheel with a plurality of interfacing rods and levers pivotally interconnected between the worm wheel and the hatch closure. This approach only addresses the movement of the hatch closure and the associated mechanism to accomplish that movement. Thus, this approach does not address the capability of the apparatus to be used in conjunction with other devices such as electric fans to effectuate active air flow movement rather than passive air flow movement. This approach also appears to lack any reference to automatic closure of the hatch upon the occurrence of an undesirable event, such as rain or snow or fire, since a purely manual system is anticipated. Also, this approach fails to address any insulating means to prevent or reduce heat loss through the apparatus while closed.
U.S. Pat. No. 2,711,682 to Drechsel discloses a power roof ventilator by essentially providing a rigid vent structure with downwardly sloping discharging baffles and movable louvers located below the centrifugal fan and fan motor. The movable louvers are designed to control the volume of air flow through the apparatus and are opened and closed by a separate motor. The movable louvers are considered closed when the louvers are horizontal and overlap each other. The air flow exiting the apparatus through the discharging baffles is primarily in the opposite direction of the air flow entering the apparatus through the louvers, consequently causing a turbulent air flow pattern which creates additional noise and requires a greater usage of electrical power to operate a more powerful fan motor. This approach, however, does not address a means for forming a positive seal in the closed position of the louvers so as to eliminate a passive air flow through the apparatus. Furthermore, this approach does not address a means for inhibiting heat loss through the apparatus while not being used.
There remains an unfilled need for a simple, quiet, and economically efficient power actuated roof vent apparatus capable of providing an effective means of removing large volumes of air from an enclosed area through the roof thereof, while addressing and overcoming the disadvantages associated with ventilation systems known in the prior art.